The invention relates to a filter cartridge of the type including a frame made of tough, rigid material that sealingly surrounds an accordion fold pack on its circumferential side. The frame is composed of plate-shaped frame elements, capable of assembly. The frame is provided, on the circumferential side along its upper and/or lower edges with a tongue that can be inserted into a latticed holder having a U-shaped profile that can be affixed therein by a viscous jointing compound.
Such a filter cartridge is known and used, for example, as an air filter in clean rooms in which microchips are manufactured. In this context, the tongue of the known filter cartridge is designed in one piece and, subject to the conditions of manufacture, in planar form, the planar tongue being adjusted to the shape of the frame. The two tongue ends, adjacent to each other, are pressed onto each other and sealingly bonded. One disadvantage of the design approach in the above-mentioned filter cartridge lies in the difficulties attendant to the manufacturing process by which the tongue is coated or anodized. A further disadvantage of the known design is that the tongue ends, which are glued to each other in the area of their junction, have only slight mechanical strength. The bond between the two ends can easily be destroyed as the filter cartridge is mounted into the holder.